loader/preloader.c

   1 /*
   2  * Preloader for ld.so
   3  *
   4  * Copyright (C) 1995,96,97,98,99,2000,2001,2002 Free Software Foundation, Inc.
   5  * Copyright (C) 2004 Mike McCormack for CodeWeavers
   6  * Copyright (C) 2004 Alexandre Julliard
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 /*
  24  * Design notes
  25  *
  26  * The goal of this program is to be a workaround for exec-shield, as used
  27  *  by the Linux kernel distributed with Fedora Core and other distros.
  28  *
  29  * To do this, we implement our own shared object loader that reserves memory
  30  * that is important to Wine, and then loads the main binary and its ELF
  31  * interpreter.
  32  *
  33  * We will try to set up the stack and memory area so that the program that
  34  * loads after us (eg. the wine binary) never knows we were here, except that
  35  * areas of memory it needs are already magically reserved.
  36  *
  37  * The following memory areas are important to Wine:
  38  *  0x00000000 - 0x00110000  the DOS area
  39  *  0x80000000 - 0x81000000  the shared heap
  40  *  ???        - ???         the PE binary load address (usually starting at 0x00400000)
  41  *
  42  * If this program is used as the shared object loader, the only difference
  43  * that the loaded programs should see is that this loader will be mapped
  44  * into memory when it starts.
  45  */
  46
  47 /*
  48  * References (things I consulted to understand how ELF loading works):
  49  *
  50  * glibc 2.3.2   elf/dl-load.c
  51  *  http://www.gnu.org/directory/glibc.html
  52  *
  53  * Linux 2.6.4   fs/binfmt_elf.c
  54  *  ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.4.tar.bz2
  55  *
  56  * Userland exec, by <grugq@hcunix.net>
  57  *  http://cert.uni-stuttgart.de/archive/bugtraq/2004/01/msg00002.html
  58  *
  59  * The ELF specification:
  60  *  http://www.linuxbase.org/spec/booksets/LSB-Embedded/LSB-Embedded/book387.html
  61  */
  62
  63 #include "config.h"
  64 #include "wine/port.h"
  65
  66 #include <stdarg.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70 #include <sys/types.h>
  71 #ifdef HAVE_SYS_STAT_H
  72 # include <sys/stat.h>
  73 #endif
  74 #include <fcntl.h>
  75 #ifdef HAVE_SYS_MMAN_H
  76 # include <sys/mman.h>
  77 #endif
  78 #ifdef HAVE_SYS_SYSCALL_H
  79 # include <sys/syscall.h>
  80 #endif
  81 #ifdef HAVE_UNISTD_H
  82 # include <unistd.h>
  83 #endif
  84 #ifdef HAVE_ELF_H
  85 # include <elf.h>
  86 #endif
  87 #ifdef HAVE_LINK_H
  88 # include <link.h>
  89 #endif
  90 #ifdef HAVE_SYS_LINK_H
  91 # include <sys/link.h>
  92 #endif
  93
  94 #include "main.h"
  95
  96 /* ELF definitions */
  97 #define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
  98 #define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
  99
 100 #define MAP_BASE_ADDR(l)     0
 101
 102 #ifndef MAP_COPY
 103 #define MAP_COPY MAP_PRIVATE
 104 #endif
 105 #ifndef MAP_NORESERVE
 106 #define MAP_NORESERVE 0
 107 #endif
 108
 109 static struct wine_preload_info preload_info[] =
 110 {
 111     { (void *)0x00000000, 0x00110000 },  /* DOS area */
 112     { (void *)0x7ffe0000, 0x01020000 },  /* shared user data + shared heap */
 113     { (void *)0x00110000, 0x1fef0000 },  /* PE exe range (may be set with WINEPRELOADRESERVE), defaults to 512mb */
 114     { 0, 0 }                             /* end of list */
 115 };
 116
 117 /* debugging */
 118 #undef DUMP_SEGMENTS
 119 #undef DUMP_AUX_INFO
 120 #undef DUMP_SYMS
 121
 122 /* older systems may not define these */
 123 #ifndef PT_TLS
 124 #define PT_TLS 7
 125 #endif
 126
 127 #ifndef AT_SYSINFO
 128 #define AT_SYSINFO 32
 129 #endif
 130 #ifndef AT_SYSINFO_EHDR
 131 #define AT_SYSINFO_EHDR 33
 132 #endif
 133
 134 static unsigned int page_size, page_mask;
 135 static char *preloader_start, *preloader_end;
 136
 137 struct wld_link_map {
 138     ElfW(Addr) l_addr;
 139     ElfW(Dyn) *l_ld;
 140     ElfW(Phdr)*l_phdr;
 141     ElfW(Addr) l_entry;
 142     ElfW(Half) l_ldnum;
 143     ElfW(Half) l_phnum;
 144     ElfW(Addr) l_map_start, l_map_end;
 145     ElfW(Addr) l_interp;
 146 };
 147
 148
 149 /*
 150  * The __bb_init_func is an empty function only called when file is
 151  * compiled with gcc flags "-fprofile-arcs -ftest-coverage".  This
 152  * function is normally provided by libc's startup files, but since we
 153  * build the preloader with "-nostartfiles -nodefaultlibs", we have to
 154  * provide our own (empty) version, otherwise linker fails.
 155  */
 156 void __bb_init_func() { return; }
 157
 158
 159 /*
 160  * The _start function is the entry and exit point of this program
 161  *
 162  *  It calls wld_start, passing a pointer to the args it receives
 163  *  then jumps to the address wld_start returns.
 164  */
 165 void _start();
 166 extern char _end[];
 167 __ASM_GLOBAL_FUNC(_start,
 168                   "\tmovl %esp,%eax\n"
 169                   "\tleal -136(%esp),%esp\n"  /* allocate some space for extra aux values */
 170                   "\tpushl %eax\n"            /* orig stack pointer */
 171                   "\tpushl %esp\n"            /* ptr to orig stack pointer */
 172                   "\tcall wld_start\n"
 173                   "\tpopl %ecx\n"             /* remove ptr to stack pointer */
 174                   "\tpopl %esp\n"             /* new stack pointer */
 175                   "\tpush %eax\n"             /* ELF interpreter entry point */
 176                   "\txor %eax,%eax\n"
 177                   "\txor %ecx,%ecx\n"
 178                   "\txor %edx,%edx\n"
 179                   "\tret\n")
 180
 181 /* wrappers for Linux system calls */
 182
 183 #define SYSCALL_RET(ret) (((ret) < 0 && (ret) > -4096) ? -1 : (ret))
 184
 185 static inline __attribute__((noreturn)) void wld_exit( int code )
 186 {
 187     for (;;)  /* avoid warning */
 188         __asm__ __volatile__( "pushl %%ebx; movl %1,%%ebx; int $0x80; popl %%ebx"
 189                               : : "a" (SYS_exit), "r" (code) );
 190 }
 191
 192 static inline int wld_open( const char *name, int flags )
 193 {
 194     int ret;
 195     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 196                           : "=a" (ret) : "0" (SYS_open), "r" (name), "c" (flags) );
 197     return SYSCALL_RET(ret);
 198 }
 199
 200 static inline int wld_close( int fd )
 201 {
 202     int ret;
 203     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 204                           : "=a" (ret) : "0" (SYS_close), "r" (fd) );
 205     return SYSCALL_RET(ret);
 206 }
 207
 208 static inline ssize_t wld_read( int fd, void *buffer, size_t len )
 209 {
 210     int ret;
 211     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 212                           : "=a" (ret)
 213                           : "0" (SYS_read), "r" (fd), "c" (buffer), "d" (len)
 214                           : "memory" );
 215     return SYSCALL_RET(ret);
 216 }
 217
 218 static inline ssize_t wld_write( int fd, const void *buffer, size_t len )
 219 {
 220     int ret;
 221     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 222                           : "=a" (ret) : "0" (SYS_write), "r" (fd), "c" (buffer), "d" (len) );
 223     return SYSCALL_RET(ret);
 224 }
 225
 226 static inline int wld_mprotect( const void *addr, size_t len, int prot )
 227 {
 228     int ret;
 229     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 230                           : "=a" (ret) : "0" (SYS_mprotect), "r" (addr), "c" (len), "d" (prot) );
 231     return SYSCALL_RET(ret);
 232 }
 233
 234 static void *wld_mmap( void *start, size_t len, int prot, int flags, int fd, off_t offset )
 235 {
 236     int ret;
 237
 238     struct
 239     {
 240         void        *addr;
 241         unsigned int length;
 242         unsigned int prot;
 243         unsigned int flags;
 244         unsigned int fd;
 245         unsigned int offset;
 246     } args;
 247
 248     args.addr   = start;
 249     args.length = len;
 250     args.prot   = prot;
 251     args.flags  = flags;
 252     args.fd     = fd;
 253     args.offset = offset;
 254     __asm__ __volatile__( "pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx"
 255                           : "=a" (ret) : "0" (SYS_mmap), "q" (&args) : "memory" );
 256     return (void *)SYSCALL_RET(ret);
 257 }
 258
 259 static inline uid_t wld_getuid(void)
 260 {
 261     uid_t ret;
 262     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getuid) );
 263     return ret;
 264 }
 265
 266 static inline uid_t wld_geteuid(void)
 267 {
 268     uid_t ret;
 269     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_geteuid) );
 270     return ret;
 271 }
 272
 273 static inline gid_t wld_getgid(void)
 274 {
 275     gid_t ret;
 276     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getgid) );
 277     return ret;
 278 }
 279
 280 static inline gid_t wld_getegid(void)
 281 {
 282     gid_t ret;
 283     __asm__( "int $0x80" : "=a" (ret) : "0" (SYS_getegid) );
 284     return ret;
 285 }
 286
 287
 288 /* replacement for libc functions */
 289
 290 static int wld_strcmp( const char *str1, const char *str2 )
 291 {
 292     while (*str1 && (*str1 == *str2)) { str1++; str2++; }
 293     return *str1 - *str2;
 294 }
 295
 296 static int wld_strncmp( const char *str1, const char *str2, size_t len )
 297 {
 298     if (len <= 0) return 0;
 299     while ((--len > 0) && *str1 && (*str1 == *str2)) { str1++; str2++; }
 300     return *str1 - *str2;
 301 }
 302
 303 static inline void *wld_memset( void *dest, int val, size_t len )
 304 {
 305     char *dst = dest;
 306     while (len--) *dst++ = val;
 307     return dest;
 308 }
 309
 310 /*
 311  * wld_printf - just the basics
 312  *
 313  *  %x prints a hex number
 314  *  %s prints a string
 315  */
 316 static int wld_vsprintf(char *buffer, const char *fmt, va_list args )
 317 {
 318     static const char hex_chars[16] = "0123456789abcdef";
 319     const char *p = fmt;
 320     char *str = buffer;
 321
 322     while( *p )
 323     {
 324         if( *p == '%' )
 325         {
 326             p++;
 327             if( *p == 'x' )
 328             {
 329                 int i;
 330                 unsigned int x = va_arg( args, unsigned int );
 331                 for(i=7; i>=0; i--)
 332                     *str++ = hex_chars[(x>>(i*4))&0xf];
 333             }
 334             else if( *p == 's' )
 335             {
 336                 char *s = va_arg( args, char * );
 337                 while(*s)
 338                     *str++ = *s++;
 339             }
 340             else if( *p == 0 )
 341                 break;
 342             p++;
 343         }
 344         *str++ = *p++;
 345     }
 346     *str = 0;
 347     return str - buffer;
 348 }
 349
 350 static void wld_printf(const char *fmt, ... )
 351 {
 352     va_list args;
 353     char buffer[256];
 354     int len;
 355
 356     va_start( args, fmt );
 357     len = wld_vsprintf(buffer, fmt, args );
 358     va_end( args );
 359     wld_write(2, buffer, len);
 360 }
 361
 362 static __attribute__((noreturn)) void fatal_error(const char *fmt, ... )
 363 {
 364     va_list args;
 365     char buffer[256];
 366     int len;
 367
 368     va_start( args, fmt );
 369     len = wld_vsprintf(buffer, fmt, args );
 370     va_end( args );
 371     wld_write(2, buffer, len);
 372     wld_exit(1);
 373 }
 374
 375 #ifdef DUMP_AUX_INFO
 376 /*
 377  *  Dump interesting bits of the ELF auxv_t structure that is passed
 378  *   as the 4th parameter to the _start function
 379  */
 380 static void dump_auxiliary( ElfW(auxv_t) *av )
 381 {
 382 #define NAME(at) { at, #at }
 383     static const struct { int val; const char *name; } names[] =
 384     {
 385         NAME(AT_BASE),
 386         NAME(AT_CLKTCK),
 387         NAME(AT_EGID),
 388         NAME(AT_ENTRY),
 389         NAME(AT_EUID),
 390         NAME(AT_FLAGS),
 391         NAME(AT_GID),
 392         NAME(AT_HWCAP),
 393         NAME(AT_PAGESZ),
 394         NAME(AT_PHDR),
 395         NAME(AT_PHENT),
 396         NAME(AT_PHNUM),
 397         NAME(AT_PLATFORM),
 398         NAME(AT_SYSINFO),
 399         NAME(AT_SYSINFO_EHDR),
 400         NAME(AT_UID),
 401         { 0, NULL }
 402     };
 403 #undef NAME
 404
 405     int i;
 406
 407     for (  ; av->a_type != AT_NULL; av++)
 408     {
 409         for (i = 0; names[i].name; i++) if (names[i].val == av->a_type) break;
 410         if (names[i].name) wld_printf("%s = %x\n", names[i].name, av->a_un.a_val);
 411         else wld_printf( "%x = %x\n", av->a_type, av->a_un.a_val );
 412     }
 413 }
 414 #endif
 415
 416 /*
 417  * set_auxiliary_values
 418  *
 419  * Set the new auxiliary values
 420  */
 421 static void set_auxiliary_values( ElfW(auxv_t) *av, const ElfW(auxv_t) *new_av,
 422                                   const ElfW(auxv_t) *delete_av, void **stack )
 423 {
 424     int i, j, av_count = 0, new_count = 0, delete_count = 0;
 425     char *src, *dst;
 426
 427     /* count how many aux values we have already */
 428     while (av[av_count].a_type != AT_NULL) av_count++;
 429
 430     /* delete unwanted values */
 431     for (j = 0; delete_av[j].a_type != AT_NULL; j++)
 432     {
 433         for (i = 0; i < av_count; i++) if (av[i].a_type == delete_av[j].a_type)
 434         {
 435             av[i].a_type = av[av_count-1].a_type;
 436             av[i].a_un.a_val = av[av_count-1].a_un.a_val;
 437             av[--av_count].a_type = AT_NULL;
 438             delete_count++;
 439             break;
 440         }
 441     }
 442
 443     /* count how many values we have in new_av that aren't in av */
 444     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 445     {
 446         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 447         if (i == av_count) new_count++;
 448     }
 449
 450     src = (char *)*stack;
 451     dst = src - (new_count - delete_count) * sizeof(*av);
 452     if (new_count > delete_count)   /* need to make room for the extra values */
 453     {
 454         int len = (char *)(av + av_count + 1) - src;
 455         for (i = 0; i < len; i++) dst[i] = src[i];
 456     }
 457     else if (new_count < delete_count)  /* get rid of unused values */
 458     {
 459         int len = (char *)(av + av_count + 1) - dst;
 460         for (i = len - 1; i >= 0; i--) dst[i] = src[i];
 461     }
 462     *stack = dst;
 463     av -= (new_count - delete_count);
 464
 465     /* now set the values */
 466     for (j = 0; new_av[j].a_type != AT_NULL; j++)
 467     {
 468         for (i = 0; i < av_count; i++) if (av[i].a_type == new_av[j].a_type) break;
 469         if (i < av_count) av[i].a_un.a_val = new_av[j].a_un.a_val;
 470         else
 471         {
 472             av[av_count].a_type     = new_av[j].a_type;
 473             av[av_count].a_un.a_val = new_av[j].a_un.a_val;
 474             av_count++;
 475         }
 476     }
 477
 478 #ifdef DUMP_AUX_INFO
 479     wld_printf("New auxiliary info:\n");
 480     dump_auxiliary( av );
 481 #endif
 482 }
 483
 484 /*
 485  * get_auxiliary
 486  *
 487  * Get a field of the auxiliary structure
 488  */
 489 static int get_auxiliary( ElfW(auxv_t) *av, int type, int def_val )
 490 {
 491   for ( ; av->a_type != AT_NULL; av++)
 492       if( av->a_type == type ) return av->a_un.a_val;
 493   return def_val;
 494 }
 495
 496 /*
 497  * map_so_lib
 498  *
 499  * modelled after _dl_map_object_from_fd() from glibc-2.3.1/elf/dl-load.c
 500  *
 501  * This function maps the segments from an ELF object, and optionally
 502  *  stores information about the mapping into the auxv_t structure.
 503  */
 504 static void map_so_lib( const char *name, struct wld_link_map *l)
 505 {
 506     int fd;
 507     unsigned char buf[0x800];
 508     ElfW(Ehdr) *header = (ElfW(Ehdr)*)buf;
 509     ElfW(Phdr) *phdr, *ph;
 510     /* Scan the program header table, collecting its load commands.  */
 511     struct loadcmd
 512       {
 513         ElfW(Addr) mapstart, mapend, dataend, allocend;
 514         off_t mapoff;
 515         int prot;
 516       } loadcmds[16], *c;
 517     size_t nloadcmds = 0, maplength;
 518
 519     fd = wld_open( name, O_RDONLY );
 520     if (fd == -1) fatal_error("%s: could not open\n", name );
 521
 522     if (wld_read( fd, buf, sizeof(buf) ) != sizeof(buf))
 523         fatal_error("%s: failed to read ELF header\n", name);
 524
 525     phdr = (void*) (((unsigned char*)buf) + header->e_phoff);
 526
 527     if( ( header->e_ident[0] != 0x7f ) ||
 528         ( header->e_ident[1] != 'E' ) ||
 529         ( header->e_ident[2] != 'L' ) ||
 530         ( header->e_ident[3] != 'F' ) )
 531         fatal_error( "%s: not an ELF binary... don't know how to load it\n", name );
 532
 533     if( header->e_machine != EM_386 )
 534         fatal_error("%s: not an i386 ELF binary... don't know how to load it\n", name );
 535
 536     if (header->e_phnum > sizeof(loadcmds)/sizeof(loadcmds[0]))
 537         fatal_error( "%s: oops... not enough space for load commands\n", name );
 538
 539     maplength = header->e_phnum * sizeof (ElfW(Phdr));
 540     if (header->e_phoff + maplength > sizeof(buf))
 541         fatal_error( "%s: oops... not enough space for ELF headers\n", name );
 542
 543     l->l_ld = 0;
 544     l->l_addr = 0;
 545     l->l_phdr = 0;
 546     l->l_phnum = header->e_phnum;
 547     l->l_entry = header->e_entry;
 548     l->l_interp = 0;
 549
 550     for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
 551     {
 552
 553 #ifdef DUMP_SEGMENTS
 554       wld_printf( "ph = %x\n", ph );
 555       wld_printf( " p_type   = %x\n", ph->p_type );
 556       wld_printf( " p_flags  = %x\n", ph->p_flags );
 557       wld_printf( " p_offset = %x\n", ph->p_offset );
 558       wld_printf( " p_vaddr  = %x\n", ph->p_vaddr );
 559       wld_printf( " p_paddr  = %x\n", ph->p_paddr );
 560       wld_printf( " p_filesz = %x\n", ph->p_filesz );
 561       wld_printf( " p_memsz  = %x\n", ph->p_memsz );
 562       wld_printf( " p_align  = %x\n", ph->p_align );
 563 #endif
 564
 565       switch (ph->p_type)
 566         {
 567           /* These entries tell us where to find things once the file's
 568              segments are mapped in.  We record the addresses it says
 569              verbatim, and later correct for the run-time load address.  */
 570         case PT_DYNAMIC:
 571           l->l_ld = (void *) ph->p_vaddr;
 572           l->l_ldnum = ph->p_memsz / sizeof (Elf32_Dyn);
 573           break;
 574
 575         case PT_PHDR:
 576           l->l_phdr = (void *) ph->p_vaddr;
 577           break;
 578
 579         case PT_LOAD:
 580           {
 581             if ((ph->p_align & page_mask) != 0)
 582               fatal_error( "%s: ELF load command alignment not page-aligned\n", name );
 583
 584             if (((ph->p_vaddr - ph->p_offset) & (ph->p_align - 1)) != 0)
 585               fatal_error( "%s: ELF load command address/offset not properly aligned\n", name );
 586
 587             c = &loadcmds[nloadcmds++];
 588             c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
 589             c->mapend = ((ph->p_vaddr + ph->p_filesz + page_mask) & ~page_mask);
 590             c->dataend = ph->p_vaddr + ph->p_filesz;
 591             c->allocend = ph->p_vaddr + ph->p_memsz;
 592             c->mapoff = ph->p_offset & ~(ph->p_align - 1);
 593
 594             c->prot = 0;
 595             if (ph->p_flags & PF_R)
 596               c->prot |= PROT_READ;
 597             if (ph->p_flags & PF_W)
 598               c->prot |= PROT_WRITE;
 599             if (ph->p_flags & PF_X)
 600               c->prot |= PROT_EXEC;
 601           }
 602           break;
 603
 604         case PT_INTERP:
 605           l->l_interp = ph->p_vaddr;
 606           break;
 607
 608         case PT_TLS:
 609           /*
 610            * We don't need to set anything up because we're
 611            * emulating the kernel, not ld-linux.so.2
 612            * The ELF loader will set up the TLS data itself.
 613            */
 614         case PT_SHLIB:
 615         case PT_NOTE:
 616         default:
 617           break;
 618         }
 619     }
 620
 621     /* Now process the load commands and map segments into memory.  */
 622     c = loadcmds;
 623
 624     /* Length of the sections to be loaded.  */
 625     maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
 626
 627     if( header->e_type == ET_DYN )
 628     {
 629         ElfW(Addr) mappref;
 630         mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
 631                    - MAP_BASE_ADDR (l));
 632
 633         /* Remember which part of the address space this object uses.  */
 634         l->l_map_start = (ElfW(Addr)) wld_mmap ((void *) mappref, maplength,
 635                                               c->prot, MAP_COPY | MAP_FILE,
 636                                               fd, c->mapoff);
 637         /* wld_printf("set  : offset = %x\n", c->mapoff); */
 638         /* wld_printf("l->l_map_start = %x\n", l->l_map_start); */
 639
 640         l->l_map_end = l->l_map_start + maplength;
 641         l->l_addr = l->l_map_start - c->mapstart;
 642
 643         wld_mprotect ((caddr_t) (l->l_addr + c->mapend),
 644                     loadcmds[nloadcmds - 1].allocend - c->mapend,
 645                     PROT_NONE);
 646         goto postmap;
 647     }
 648     else
 649     {
 650         /* sanity check */
 651         if ((char *)c->mapstart + maplength > preloader_start &&
 652             (char *)c->mapstart <= preloader_end)
 653             fatal_error( "%s: binary overlaps preloader (%x-%x)\n",
 654                          name, c->mapstart, (char *)c->mapstart + maplength );
 655
 656         ELF_FIXED_ADDRESS (loader, c->mapstart);
 657     }
 658
 659     /* Remember which part of the address space this object uses.  */
 660     l->l_map_start = c->mapstart + l->l_addr;
 661     l->l_map_end = l->l_map_start + maplength;
 662
 663     while (c < &loadcmds[nloadcmds])
 664       {
 665         if (c->mapend > c->mapstart)
 666             /* Map the segment contents from the file.  */
 667             wld_mmap ((void *) (l->l_addr + c->mapstart),
 668                         c->mapend - c->mapstart, c->prot,
 669                         MAP_FIXED | MAP_COPY | MAP_FILE, fd, c->mapoff);
 670
 671       postmap:
 672         if (l->l_phdr == 0
 673             && (ElfW(Off)) c->mapoff <= header->e_phoff
 674             && ((size_t) (c->mapend - c->mapstart + c->mapoff)
 675                 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
 676           /* Found the program header in this segment.  */
 677           l->l_phdr = (void *)(unsigned int) (c->mapstart + header->e_phoff - c->mapoff);
 678
 679         if (c->allocend > c->dataend)
 680           {
 681             /* Extra zero pages should appear at the end of this segment,
 682                after the data mapped from the file.   */
 683             ElfW(Addr) zero, zeroend, zeropage;
 684
 685             zero = l->l_addr + c->dataend;
 686             zeroend = l->l_addr + c->allocend;
 687             zeropage = (zero + page_mask) & ~page_mask;
 688
 689             /*
 690              * This is different from the dl-load load...
 691              *  ld-linux.so.2 relies on the whole page being zero'ed
 692              */
 693             zeroend = (zeroend + page_mask) & ~page_mask;
 694
 695             if (zeroend < zeropage)
 696             {
 697               /* All the extra data is in the last page of the segment.
 698                  We can just zero it.  */
 699               zeropage = zeroend;
 700             }
 701
 702             if (zeropage > zero)
 703               {
 704                 /* Zero the final part of the last page of the segment.  */
 705                 if ((c->prot & PROT_WRITE) == 0)
 706                   {
 707                     /* Dag nab it.  */
 708                     wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot|PROT_WRITE);
 709                   }
 710                 wld_memset ((void *) zero, '\0', zeropage - zero);
 711                 if ((c->prot & PROT_WRITE) == 0)
 712                   wld_mprotect ((caddr_t) (zero & ~page_mask), page_size, c->prot);
 713               }
 714
 715             if (zeroend > zeropage)
 716               {
 717                 /* Map the remaining zero pages in from the zero fill FD.  */
 718                 caddr_t mapat;
 719                 mapat = wld_mmap ((caddr_t) zeropage, zeroend - zeropage,
 720                                 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
 721                                 -1, 0);
 722               }
 723           }
 724
 725         ++c;
 726       }
 727
 728     if (l->l_phdr == NULL) fatal_error("no program header\n");
 729
 730     l->l_phdr = (void *)((ElfW(Addr))l->l_phdr + l->l_addr);
 731     l->l_entry += l->l_addr;
 732
 733     wld_close( fd );
 734 }
 735
 736
 737 /*
 738  * Find a symbol in the symbol table of the executable loaded
 739  */
 740 static void *find_symbol( const ElfW(Phdr) *phdr, int num, const char *var )
 741 {
 742     const ElfW(Dyn) *dyn = NULL;
 743     const ElfW(Phdr) *ph;
 744     const ElfW(Sym) *symtab = NULL;
 745     const char *strings = NULL;
 746     uint32_t i, symtabend = 0;
 747
 748     /* check the values */
 749 #ifdef DUMP_SYMS
 750     wld_printf("%x %x\n", phdr, num );
 751 #endif
 752     if( ( phdr == NULL ) || ( num == 0 ) )
 753     {
 754         wld_printf("could not find PT_DYNAMIC header entry\n");
 755         return NULL;
 756     }
 757
 758     /* parse the (already loaded) ELF executable's header */
 759     for (ph = phdr; ph < &phdr[num]; ++ph)
 760     {
 761         if( PT_DYNAMIC == ph->p_type )
 762         {
 763             dyn = (void *) ph->p_vaddr;
 764             num = ph->p_memsz / sizeof (Elf32_Dyn);
 765             break;
 766         }
 767     }
 768     if( !dyn ) return NULL;
 769
 770     while( dyn->d_tag )
 771     {
 772         if( dyn->d_tag == DT_STRTAB )
 773             strings = (const char*) dyn->d_un.d_ptr;
 774         if( dyn->d_tag == DT_SYMTAB )
 775             symtab = (const ElfW(Sym) *)dyn->d_un.d_ptr;
 776         if( dyn->d_tag == DT_HASH )
 777             symtabend = *((const uint32_t *)dyn->d_un.d_ptr + 1);
 778 #ifdef DUMP_SYMS
 779         wld_printf("%x %x\n", dyn->d_tag, dyn->d_un.d_ptr );
 780 #endif
 781         dyn++;
 782     }
 783
 784     if( (!symtab) || (!strings) ) return NULL;
 785
 786     for (i = 0; i < symtabend; i++)
 787     {
 788         if( ( ELF32_ST_BIND(symtab[i].st_info) == STT_OBJECT ) &&
 789             ( 0 == wld_strcmp( strings+symtab[i].st_name, var ) ) )
 790         {
 791 #ifdef DUMP_SYMS
 792             wld_printf("Found %s -> %x\n", strings+symtab[i].st_name, symtab[i].st_value );
 793 #endif
 794             return (void*)symtab[i].st_value;
 795         }
 796     }
 797     return NULL;
 798 }
 799
 800 /*
 801  *  preload_reserve
 802  *
 803  * Reserve a range specified in string format
 804  */
 805 static void preload_reserve( const char *str )
 806 {
 807     const char *p;
 808     unsigned long result = 0;
 809     void *start = NULL, *end = NULL;
 810     int first = 1;
 811
 812     for (p = str; *p; p++)
 813     {
 814         if (*p >= '0' && *p <= '9') result = result * 16 + *p - '0';
 815         else if (*p >= 'a' && *p <= 'f') result = result * 16 + *p - 'a' + 10;
 816         else if (*p >= 'A' && *p <= 'F') result = result * 16 + *p - 'A' + 10;
 817         else if (*p == '-')
 818         {
 819             if (!first) goto error;
 820             start = (void *)(result & ~page_mask);
 821             result = 0;
 822             first = 0;
 823         }
 824         else goto error;
 825     }
 826     if (!first) end = (void *)((result + page_mask) & ~page_mask);
 827     else if (result) goto error;  /* single value '0' is allowed */
 828
 829     /* sanity checks */
 830     if (end <= start) start = end = NULL;
 831     else if ((char *)end > preloader_start &&
 832              (char *)start <= preloader_end)
 833     {
 834         wld_printf( "WINEPRELOADRESERVE range %x-%x overlaps preloader %x-%x\n",
 835                      start, end, preloader_start, preloader_end );
 836         start = end = NULL;
 837     }
 838
 839     /* entry 2 is for the PE exe */
 840     preload_info[2].addr = start;
 841     preload_info[2].size = (char *)end - (char *)start;
 842     return;
 843
 844 error:
 845     fatal_error( "invalid WINEPRELOADRESERVE value '%s'\n", str );
 846 }
 847
 848 /*
 849  *  is_in_preload_range
 850  *
 851  * Check if address of the given aux value is in one of the reserved ranges
 852  */
 853 static int is_in_preload_range( const ElfW(auxv_t) *av, int type )
 854 {
 855     int i;
 856
 857     while (av->a_type != type && av->a_type != AT_NULL) av++;
 858
 859     if (av->a_type == type)
 860     {
 861         for (i = 0; preload_info[i].size; i++)
 862         {
 863             if ((char *)av->a_un.a_val >= (char *)preload_info[i].addr &&
 864                 (char *)av->a_un.a_val < (char *)preload_info[i].addr + preload_info[i].size)
 865                 return 1;
 866         }
 867     }
 868     return 0;
 869 }
 870
 871 /*
 872  *  wld_start
 873  *
 874  *  Repeat the actions the kernel would do when loading a dynamically linked .so
 875  *  Load the binary and then its ELF interpreter.
 876  *  Note, we assume that the binary is a dynamically linked ELF shared object.
 877  */
 878 void* wld_start( void **stack )
 879 {
 880     int i, *pargc;
 881     char **argv, **p;
 882     char *interp, *reserve = NULL;
 883     ElfW(auxv_t) new_av[12], delete_av[3], *av;
 884     struct wld_link_map main_binary_map, ld_so_map;
 885     struct wine_preload_info **wine_main_preload_info;
 886
 887     pargc = *stack;
 888     argv = (char **)pargc + 1;
 889     if (*pargc < 2) fatal_error( "Usage: %s wine_binary [args]\n", argv[0] );
 890
 891     /* skip over the parameters */
 892     p = argv + *pargc + 1;
 893
 894     /* skip over the environment */
 895     while (*p)
 896     {
 897         static const char res[] = "WINEPRELOADRESERVE=";
 898         if (!wld_strncmp( *p, res, sizeof(res)-1 )) reserve = *p + sizeof(res) - 1;
 899         p++;
 900     }
 901
 902     av = (ElfW(auxv_t)*) (p+1);
 903     page_size = get_auxiliary( av, AT_PAGESZ, 4096 );
 904     page_mask = page_size - 1;
 905
 906     preloader_start = (char *)_start - ((unsigned int)_start & page_mask);
 907     preloader_end = (char *)((unsigned int)(_end + page_mask) & ~page_mask);
 908
 909 #ifdef DUMP_AUX_INFO
 910     wld_printf( "stack = %x\n", *stack );
 911     for( i = 0; i < *pargc; i++ ) wld_printf("argv[%x] = %s\n", i, argv[i]);
 912     dump_auxiliary( av );
 913 #endif
 914
 915     /* reserve memory that Wine needs */
 916     if (reserve) preload_reserve( reserve );
 917     for (i = 0; preload_info[i].size; i++)
 918         wld_mmap( preload_info[i].addr, preload_info[i].size,
 919                   PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0 );
 920
 921     /* load the main binary */
 922     map_so_lib( argv[1], &main_binary_map );
 923
 924     /* load the ELF interpreter */
 925     interp = (char *)main_binary_map.l_addr + main_binary_map.l_interp;
 926     map_so_lib( interp, &ld_so_map );
 927
 928     /* store pointer to the preload info into the appropriate main binary variable */
 929     wine_main_preload_info = find_symbol( main_binary_map.l_phdr, main_binary_map.l_phnum,
 930                                           "wine_main_preload_info" );
 931     if (wine_main_preload_info) *wine_main_preload_info = preload_info;
 932     else wld_printf( "wine_main_preload_info not found\n" );
 933
 934 #define SET_NEW_AV(n,type,val) new_av[n].a_type = (type); new_av[n].a_un.a_val = (val);
 935     SET_NEW_AV( 0, AT_PHDR, (unsigned long)main_binary_map.l_phdr );
 936     SET_NEW_AV( 1, AT_PHENT, sizeof(ElfW(Phdr)) );
 937     SET_NEW_AV( 2, AT_PHNUM, main_binary_map.l_phnum );
 938     SET_NEW_AV( 3, AT_PAGESZ, page_size );
 939     SET_NEW_AV( 4, AT_BASE, ld_so_map.l_addr );
 940     SET_NEW_AV( 5, AT_FLAGS, get_auxiliary( av, AT_FLAGS, 0 ) );
 941     SET_NEW_AV( 6, AT_ENTRY, main_binary_map.l_entry );
 942     SET_NEW_AV( 7, AT_UID, get_auxiliary( av, AT_UID, wld_getuid() ) );
 943     SET_NEW_AV( 8, AT_EUID, get_auxiliary( av, AT_EUID, wld_geteuid() ) );
 944     SET_NEW_AV( 9, AT_GID, get_auxiliary( av, AT_GID, wld_getgid() ) );
 945     SET_NEW_AV(10, AT_EGID, get_auxiliary( av, AT_EGID, wld_getegid() ) );
 946     SET_NEW_AV(11, AT_NULL, 0 );
 947 #undef SET_NEW_AV
 948
 949     i = 0;
 950     /* delete sysinfo values if addresses conflict */
 951     if (is_in_preload_range( av, AT_SYSINFO )) delete_av[i++].a_type = AT_SYSINFO;
 952     if (is_in_preload_range( av, AT_SYSINFO_EHDR )) delete_av[i++].a_type = AT_SYSINFO_EHDR;
 953     delete_av[i].a_type = AT_NULL;
 954
 955     /* get rid of first argument */
 956     pargc[1] = pargc[0] - 1;
 957     *stack = pargc + 1;
 958
 959     set_auxiliary_values( av, new_av, delete_av, stack );
 960
 961 #ifdef DUMP_AUX_INFO
 962     wld_printf("new stack = %x\n", *stack);
 963     wld_printf("jumping to %x\n", ld_so_map.l_entry);
 964 #endif
 965
 966     return (void *)ld_so_map.l_entry;
 967 }